Nitrogen in interstitial waters in the Sahel : natural baseline, pollutant or resource?

Nitrate in the unsaturated zone between the soil surface and the water table was studied in agroforestry Parklands in north western Senegal by examination of samples obtained by hand auger. Depending on location, water tables existed at depths between 10 and 35m below ground. Previous studies of groundwater in this region had found that large concentrations of nitrate were unconnected with anthropogenic activity. The objective of this study was to determine whether nitrogen fixing vegetation had a role in groundwater nitrate accumulation and whether roots of trees were located deeply enough to access the nitrate. Accordingly, sample profiles were augered close to stems of nitrogen fixing trees, non-nitrogen fixing trees and also in adjacent areas that were unaffected by tree presence. These adjacent areas were typically open pasture or cultivated fields. Tree fine roots were quantified in the samples and examined for the presence of mycorrhizas. Similarly, sand/soil samples were examined and tested for the presence of nitrogen fixing rhizobia that were capable of forming functional nodules on appropriate host plants. Concentrations of nitrate were greatest in soils beneath nitrogen fixing trees and nitrate was more plentiful in profiles augered beneath nitrogen fixing crops than it was elsewhere suggesting that N-fixation was the source of the nitrate. The concentrrations of nitrate that were found in the unsaturated zone were greatly in excess of the WHO recommended limit for nitrate in drinking water. High NO3-N/Cl ratios confirm insitu production of nitrate, and indicate that this is a natural baseline occurrence related to N-fixation. The nitrate is moving down the profile and impacts the groundwater unless it can be intercepted by plant roots. NO3-N amounts in solution in the soil profile varied between 75 and 1000kg ha–1 beneath trees and between 120 and 400kg ha–1 in areas outwith tree crowns. Although these quantities of N occupy the lower end of the range of N values obtained in north American deserts, they comprise a considerable dryland resource where amounts of organic fertilizer are limited and where cost prohibits the use of commercial fertilizers. Roots of both nitrogen fixing and non-nitrogen fixing trees were deep enough to access the nitrate but the small amounts of available water at intermediate depths suggest that large scale uptake of nitrate will only be possible in the wetter zones located close to the water table. Shallow roots tended to be more heavily colonized by mycorrhizas than deeper roots but mycorrhizas were recovered from roots located 22m below ground. Tree roots and rhizobia had similar patterns of distribution. They were commonest close to the soil surface, less frequent at intermediate depths and tended to increase in frequency close to the water table

Meeting unique requirements: Community consultation and public disclosure for research in emergency setting using exception from informed consent

BackgroundException from informed consent (EFIC) regulations for research in emergency settings contain unique requirements for community consultation and public disclosure. These requirements address ethical challenges intrinsic to this research context. Multiple approaches have evolved to accomplish these activities that may reflect and advance different aims. This scoping review was designed to identify areas of consensus and lingering uncertainty in the literature.MethodsScoping review methodology was used. Conceptual and empirical literature related to community consultation and public disclosure for EFIC research was included and identified through a structured search using Embase, HEIN Online, PubMed, and Web of Science. Data were extracted using a standardized tool with domains for major literature categories.ResultsAmong 84 manuscripts, major domains included conceptual or policy issues, reports of community consultation processes and results, and reports of public disclosure processes and results. Areas of consensus related to community consultation included the need for a two‐way exchange of information and use of multiple methods. Public acceptance of personal EFIC enrollment is commonly 64% to 85%. There is less consensus regarding how to assess attitudes, what “communities” to prioritize, and how to determine adequacy for individual projects. Core goals of public disclosure are less well developed; no metrics exist for assessing adequacy.ConclusionsMultiple methods are used to meet community consultation and public disclosure requirements. There remain no settled norms for assessing adequacy of public disclosure, and there is lingering debate about needed breadth and depth of community consultation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/170817/1/acem14264_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/170817/2/acem14264.pd

‘Overcoming the Bottleneck’: Knowledge Architectures for Genomic Data Interpretation in Oncology

International audienceIn recent years, oncology transitioned from its traditional, organ-based approach to 'precision oncology' centered on molecular alterations. As a result, it has become to a significant extent a 'data-centric' domain. Its practices increasingly rely on a sophisticated techno-scientific infrastructure that generates massive amounts of data in need of consistent, appropriate interpretations. Attempts to overcome the interpretation bottleneck have led to the establishment of a complex landscape of interrelated resources that, while displaying distinct characteristics and design choices, also entertain horizontal and vertical relations. Although there is no denying that the data-centric nature of contemporary oncology raises a number of key issues related to the production and circulation of data, we suggest that the focus on data use and re-use should be complemented by a focus on interpretation. Oncology practitioners refer to data interpretation resources as 'knowledgebases', an actor's category designed to differentiate them from generic, multipurpose databases. Their major purpose is the definition and identification of clinically actionable alterations. A heavy investment in human curation, of a clinical rather than exclusively scientific nature is needed to make them valuable, but each knowledgebas